private static BasicBlock InlineIR(this CALLInstruction call,
IList<BasicBlockInstruction> preamble,
BasicBlock backend,
Dictionary<Subprogram, Dictionary<VirtualRegister, VirtualRegister>> inlineRegMaps)
{
Dictionary<VirtualRegister, VirtualRegister> inlineRegMap;
if (!inlineRegMaps.TryGetValue(call.Target, out inlineRegMap))
{
inlineRegMap = call.Target.LocalVariables.Select(lv =>
new KeyValuePair<VirtualRegister, VirtualRegister>(lv, new VirtualRegister(lv.UnderlyingType, lv.StateSpace))).
ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
inlineRegMaps.Add(call.Target, inlineRegMap);
}
inlineRegMap = inlineRegMap.Concat(call.Target.FormalParameters.Zip(call.Arguments,
(formal, actual) => new KeyValuePair<VirtualRegister, VirtualRegister>(formal,
(actual is VirtualRegister) ? (actual as VirtualRegister) :
(formal.StateSpace != StateSpaces.REG) ? new VirtualRegister(formal.UnderlyingType, formal.StateSpace) :
new VirtualRegister(formal.DataType)))).
ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
Dictionary<BasicBlock, BasicBlock> cfgmap = call.Target.GetBasicBlocks().Select(bb =>
{
VirtualRegister flag = (bb.Trailer is JumpIfInstruction) ?
(bb.Trailer as JumpIfInstruction).Flag.MapOperand(inlineRegMap) : null;
ControlFlowInstruction trailer;
switch (bb.Trailer.OpCode)
{
case IROpCodes.RET:
trailer = new JMPInstruction() { Target = backend };
break;
case IROpCodes.JMP:
trailer = new JMPInstruction();
break;
case IROpCodes.JT:
trailer = new JTInstruction(flag);
break;
case IROpCodes.JF:
trailer = new JFInstruction(flag);
break;
default:
throw new NotSupportedException();
}
return new KeyValuePair<BasicBlock, BasicBlock>(bb,
new BasicBlock(bb.Code.Select(bbi => bbi.MapInstruction(inlineRegMap)).ToList(), trailer));
}).ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
foreach (KeyValuePair<BasicBlock, BasicBlock> bbmap in cfgmap)
{
if (bbmap.Key.Successor != null)
bbmap.Value.Successor = cfgmap[bbmap.Key.Successor];
if (bbmap.Key.Target != null)
bbmap.Value.Target = cfgmap[bbmap.Key.Target];
}
BasicBlock root = cfgmap[call.Target.CFGRoot];
return new BasicBlock(preamble.Concat(root.Code).ToList(), root.Trailer);
}
private void Enumerate(BasicBlock bb, Action<BasicBlock> handler, IList<BasicBlock> visited)
{
if (bb != null && !visited.Contains(bb))
{
handler(bb);
visited.Add(bb);
Enumerate(bb.Successor, handler, visited);
Enumerate(bb.Target, handler, visited);
}
}
private static string ToPTX(this ControlFlowInstruction cfi, BasicBlock following)
{
JumpInstruction jump = cfi as JumpInstruction;
JumpIfInstruction jumpif = cfi as JumpIfInstruction;
switch (cfi.OpCode)
{
case IROpCodes.JMP:
return jump.Target == following ? "" : "bra.uni " + jump.Target.Label + ";\n";
case IROpCodes.JT:
return "setp.ne." + jumpif.Flag.DataType.ToPTX() + " %p, 0, " + jumpif.Flag + ";\n" +
"@%p bra.uni " + jump.Target.Label + ";\n" +
(jumpif.Next == following ? "" : "bra.uni " + jumpif.Next.Label + ";\n");
case IROpCodes.JF:
return "setp.eq." + jumpif.Flag.DataType.ToPTX() + " %p, 0, " + jumpif.Flag + ";\n" +
"@%p bra.uni " + jump.Target.Label + ";\n" +
(jumpif.Next == following ? "" : "bra.uni " + jumpif.Next.Label + ";\n");
case IROpCodes.RET:
return "ret;\n";
default:
throw new NotSupportedException(cfi.OpCode.ToString());
}
}
private static string ToPTX(this BasicBlock bb, BasicBlock following)
{
string bbcode = string.Join("\n", bb.Code.Select(bbi => bbi.ToPTX() + ";"));
return bb.Label + ":\n" + (bbcode != "" ? bbcode + "\n" : "") +
bb.Trailer.ToPTX(following);
}
private static BasicBlock InlineIR(this IList<BasicBlockInstruction> code,
ControlFlowInstruction trailer,
Func<Subprogram, bool> permitInline,
Dictionary<VirtualRegister, VirtualRegister> copyRegMap,
Dictionary<Subprogram, Dictionary<VirtualRegister, VirtualRegister>> inlineRegMaps,
IList<Subprogram> subprograms,
out BasicBlock backend)
{
List<BasicBlockInstruction> preamble = new List<BasicBlockInstruction>();
int i = 0;
while (i < code.Count && !(code[i].OpCode == IROpCodes.CALL &&
permitInline(subprograms.Single(sp => sp.Name == (code[i] as CALLInstruction).Target.Name))))
preamble.Add(code[i++].MapInstruction(copyRegMap));
if (i < code.Count)
{
CALLInstruction call = code[i++] as CALLInstruction;
call = new CALLInstruction(subprograms.Single(sp => sp.Name == call.Target.Name),
call.Arguments.Select(op => op.MapOperand(copyRegMap)).ToList());
List<BasicBlockInstruction> tail = new List<BasicBlockInstruction>();
while (i < code.Count)
tail.Add(code[i++]);
return call.InlineIR(preamble, tail.InlineIR(trailer, permitInline, copyRegMap,
inlineRegMaps, subprograms, out backend), inlineRegMaps);
}
else
{
backend = new BasicBlock(preamble, trailer);
return backend;
}
}
public int GetPathLength(BasicBlock s, BasicBlock t)
{
return GetPathLength(bblist.IndexOf(s), bblist.IndexOf(t));
}
public Stack<BasicBlock> GetPath(BasicBlock s, BasicBlock t)
{
return new Stack<BasicBlock>(GetPath(bblist.IndexOf(s), bblist.IndexOf(t)).Select(
i => bblist[i]).Reverse());
}
private static BasicBlock HandleBranch(
ControlFlowInstruction cfi,
BasicBlock enclosing_loop_frontier,
IList<BasicBlock> bblist,
Dictionary<BasicBlock, IEnumerable<BasicBlock>> pred,
Dictionary<BasicBlock, List<BasicBlock>> dom,
GraphPathFinder path_finder,
List<TreeStatement> code)
{
JumpInstruction jump = cfi as JumpInstruction;
JumpIfInstruction jumpif = cfi as JumpIfInstruction;
switch (cfi.OpCode)
{
case IROpCodes.RET:
return null;
case IROpCodes.JMP:
return jump.Target;
case IROpCodes.JT:
case IROpCodes.JF:
{
// loop condition check
if (jumpif.Target == enclosing_loop_frontier)
{
// while-do break condition check
code.Add(new BranchStatement(
jumpif.Flag,
cfi.OpCode == IROpCodes.JT ? new TreeStatement[] { new BreakStatement() } : null,
cfi.OpCode == IROpCodes.JF ? new TreeStatement[] { new BreakStatement() } : null));
return jumpif.Next;
}
if (jumpif.Next == enclosing_loop_frontier)
{
// do-while continue condition check
code.Add(new BranchStatement(
jumpif.Flag,
cfi.OpCode == IROpCodes.JF ? new TreeStatement[] { new BreakStatement() } : null,
cfi.OpCode == IROpCodes.JT ? new TreeStatement[] { new BreakStatement() } : null));
return jumpif.Target;
}
// initialize IF statement frontier with enclosing loop frontier or the last block in CFG
BasicBlock frontier = (enclosing_loop_frontier != null) ? enclosing_loop_frontier :
bblist.Single(bb => bb.Trailer.OpCode == IROpCodes.RET);
// precise IF statement frontier with last common block in reversed paths going
// from initial frontier value to both successors of basic block ending with this branch
IEnumerator<BasicBlock> targetPathRev =
path_finder.GetPath(jumpif.Target, frontier).Reverse().GetEnumerator();
IEnumerator<BasicBlock> nextPathRev =
path_finder.GetPath(jumpif.Next, frontier).Reverse().GetEnumerator();
while (targetPathRev.MoveNext() && nextPathRev.MoveNext() && targetPathRev.Current == nextPathRev.Current)
frontier = targetPathRev.Current;
List<TreeStatement> trueBranchCode = new List<TreeStatement>();
List<TreeStatement> falseBranchCode = new List<TreeStatement>();
BasicBlock cursor;
cursor = cfi.OpCode == IROpCodes.JT ? jumpif.Target : jumpif.Next;
while (cursor != frontier)
cursor = HandleStatement(cursor, null, bblist, pred, dom, path_finder, trueBranchCode);
cursor = cfi.OpCode == IROpCodes.JF ? jumpif.Target : jumpif.Next;
while (cursor != frontier)
cursor = HandleStatement(cursor, null, bblist, pred, dom, path_finder, falseBranchCode);
code.Add(new BranchStatement(jumpif.Flag, trueBranchCode, falseBranchCode));
return frontier;
}
default:
throw new NotSupportedException(cfi.OpCode.ToString());
}
}
private static void NumDepth(BasicBlock n, Dictionary<BasicBlock, int> dfn,
ref int c, IList<BasicBlock> visited)
{
visited.Add(n);
foreach (BasicBlock s in new [] { n.Successor, n.Target })
{
if (s != null && !visited.Contains(s))
NumDepth(s, dfn, ref c, visited);
}
dfn[n] = c--;
}
private static BasicBlock HandleStatement(
BasicBlock start,
BasicBlock enclosing_loop_frontier,
IList<BasicBlock> bblist,
Dictionary<BasicBlock, IEnumerable<BasicBlock>> pred,
Dictionary<BasicBlock, List<BasicBlock>> dom,
GraphPathFinder path_finder,
List<TreeStatement> code)
{
BasicBlock loop_tail;
try
{
loop_tail = pred[start].Where(bb => dom[bb].Contains(start)).SingleOrDefault();
}
catch (InvalidOperationException e)
{
throw new IrreducibleCFGException("Loop must have only one route to its header from its body");
}
if (loop_tail != null)
{
IEnumerable<BasicBlock> loop_insiders = bblist.Where(
bb => path_finder.GetPathLength(bb, loop_tail) < (int)short.MaxValue &&
!path_finder.GetPath(bb, loop_tail).Contains(start) &&
dom[bb].Contains(start)).Add(start);
BasicBlock loop_frontier;
try
{
loop_frontier = (from insider in loop_insiders
from adj in new [] { insider.Target, insider.Successor }
where adj != null && !loop_insiders.Contains(adj)
select adj).Single();
}
catch (InvalidOperationException e)
{
throw new IrreducibleCFGException("Loop must have only one exit route from its body");
}
List<TreeStatement> loop_body = start.Code.Select(bbi => new InstructionStatement(bbi) as TreeStatement).ToList();
BasicBlock statement_cursor = HandleBranch(start.Trailer, loop_frontier, bblist, pred, dom, path_finder, loop_body);
while (statement_cursor != start)
statement_cursor = HandleStatement(statement_cursor, loop_frontier, bblist, pred, dom, path_finder, loop_body);
code.Add(new InfiniteLoopStatement(loop_body));
return loop_frontier;
}
code.AddRange(start.Code.Select(bbi => new InstructionStatement(bbi)));
return HandleBranch(start.Trailer, enclosing_loop_frontier, bblist, pred, dom, path_finder, code);
}
public static IList <TreeStatement> BuildAST(this Subprogram src)
{
IList <BasicBlock> bblist = src.GetBasicBlocks();
Dictionary <BasicBlock, IEnumerable <BasicBlock> > pred = bblist.Select(bb =>
new KeyValuePair <BasicBlock, IEnumerable <BasicBlock> >(bb,
bblist.Where(bbel => bbel.Successor == bb || bbel.Target == bb))).
ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
// Determine dominators.
Dictionary <BasicBlock, List <BasicBlock> > dom = bblist.Select(bb =>
new KeyValuePair <BasicBlock, List <BasicBlock> >(bb,
bb == src.CFGRoot ? new List <BasicBlock> {
src.CFGRoot
} : bblist.ToList())).
ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
bool changes = true;
while (changes)
{
changes = false;
foreach (BasicBlock n in bblist)
{
if (n != src.CFGRoot)
{
IEnumerable <BasicBlock> doms = null;
foreach (BasicBlock p in pred[n])
{
doms = (doms == null) ? dom[p] : doms.Intersect(dom[p]);
}
doms = doms.Union(new [] { n });
if (!doms.SequenceEqual(dom[n]))
{
changes = true;
dom[n] = new List <BasicBlock>(doms);
}
}
}
}
// Perform depth-first enumeration.
Dictionary <BasicBlock, int> dfn = bblist.Select(bb =>
new KeyValuePair <BasicBlock, int>(bb, 0)).
ToDictionary(kvp => kvp.Key, kvp => kvp.Value);
int c = bblist.Count;
NumDepth(src.CFGRoot, dfn, ref c, new List <BasicBlock>());
// Test CFG reducibility: each retreating edge must be back edge.
foreach (BasicBlock sbb in bblist)
{
foreach (BasicBlock tbb in new [] { sbb.Successor, sbb.Target })
{
if (tbb != null && dfn[tbb] < dfn[sbb] && !dom[sbb].Contains(tbb))
{
throw new IrreducibleCFGException("There is non-back retreating edge");
}
}
}
if (bblist.Where(bb => bb.Trailer.OpCode == IROpCodes.RET).Count() != 1)
{
throw new IrreducibleCFGException("Control flow graph must have single node with RET ending");
}
List <TreeStatement> code = new List <TreeStatement>();
BasicBlock cur = src.CFGRoot;
GraphPathFinder path_finder = new GraphPathFinder(bblist);
while (cur != null)
{
cur = HandleStatement(cur, null, bblist, pred, dom, path_finder, code);
}
return(code.AsReadOnly());
}
public Stack <BasicBlock> GetPath(BasicBlock s, BasicBlock t)
{
return(new Stack <BasicBlock>(GetPath(bblist.IndexOf(s), bblist.IndexOf(t)).Select(
i => bblist[i]).Reverse()));
}
public int GetPathLength(BasicBlock s, BasicBlock t)
{
return(GetPathLength(bblist.IndexOf(s), bblist.IndexOf(t)));
}
private static BasicBlock HandleBranch(
ControlFlowInstruction cfi,
BasicBlock enclosing_loop_frontier,
IList <BasicBlock> bblist,
Dictionary <BasicBlock, IEnumerable <BasicBlock> > pred,
Dictionary <BasicBlock, List <BasicBlock> > dom,
GraphPathFinder path_finder,
List <TreeStatement> code)
{
JumpInstruction jump = cfi as JumpInstruction;
JumpIfInstruction jumpif = cfi as JumpIfInstruction;
switch (cfi.OpCode)
{
case IROpCodes.RET:
return(null);
case IROpCodes.JMP:
return(jump.Target);
case IROpCodes.JT:
case IROpCodes.JF:
{
// loop condition check
if (jumpif.Target == enclosing_loop_frontier)
{
// while-do break condition check
code.Add(new BranchStatement(
jumpif.Flag,
cfi.OpCode == IROpCodes.JT ? new TreeStatement[] { new BreakStatement() } : null,
cfi.OpCode == IROpCodes.JF ? new TreeStatement[] { new BreakStatement() } : null));
return(jumpif.Next);
}
if (jumpif.Next == enclosing_loop_frontier)
{
// do-while continue condition check
code.Add(new BranchStatement(
jumpif.Flag,
cfi.OpCode == IROpCodes.JF ? new TreeStatement[] { new BreakStatement() } : null,
cfi.OpCode == IROpCodes.JT ? new TreeStatement[] { new BreakStatement() } : null));
return(jumpif.Target);
}
// initialize IF statement frontier with enclosing loop frontier or the last block in CFG
BasicBlock frontier = (enclosing_loop_frontier != null) ? enclosing_loop_frontier :
bblist.Single(bb => bb.Trailer.OpCode == IROpCodes.RET);
// precise IF statement frontier with last common block in reversed paths going
// from initial frontier value to both successors of basic block ending with this branch
IEnumerator <BasicBlock> targetPathRev =
path_finder.GetPath(jumpif.Target, frontier).Reverse().GetEnumerator();
IEnumerator <BasicBlock> nextPathRev =
path_finder.GetPath(jumpif.Next, frontier).Reverse().GetEnumerator();
while (targetPathRev.MoveNext() && nextPathRev.MoveNext() && targetPathRev.Current == nextPathRev.Current)
{
frontier = targetPathRev.Current;
}
List <TreeStatement> trueBranchCode = new List <TreeStatement>();
List <TreeStatement> falseBranchCode = new List <TreeStatement>();
BasicBlock cursor;
cursor = cfi.OpCode == IROpCodes.JT ? jumpif.Target : jumpif.Next;
while (cursor != frontier)
{
cursor = HandleStatement(cursor, null, bblist, pred, dom, path_finder, trueBranchCode);
}
cursor = cfi.OpCode == IROpCodes.JF ? jumpif.Target : jumpif.Next;
while (cursor != frontier)
{
cursor = HandleStatement(cursor, null, bblist, pred, dom, path_finder, falseBranchCode);
}
code.Add(new BranchStatement(jumpif.Flag, trueBranchCode, falseBranchCode));
return(frontier);
}
default:
throw new NotSupportedException(cfi.OpCode.ToString());
}
}
